Schematic Capture : Bus Wiring

Bus

With buses, it is possible to group wires pulled from ICs, FPGAs, etc.

The following explains how to use buses.

STEP 1: Create a bus.
STEP 2: Connect a component and the bus with wires.
STEP 3: Place labels on the wires connected to the bus to give net names.
STEP 4: Connect a port to the bus.


Drawing Buses
The following explains how to draw buses.
(1) Click [Create Schematic]
-> [Bus].
(2) Click on a sheet to start drawing a bus line.
(3) Double-click to finish drawing the line.
(4) Click [Create Schematic]
-> [Parallel Wire].

* When pulling one at a time,
select [Create Schematic]
-> [Wire]
or
[Create Schematic]
-> [Auto Wiring].
(5) Create wires from a component to the bus.
  Automatically, a ripper (angled portion of the wire connected to the bus) is created, and the wire is connected to the bus.
  * It is possible to change the size, etc., in Ripper (angled portion of the wire connected to the bus) Settings.
(6) Click [Create Schematic]
-> [Label].
(7) Enter a label name and then click "OK".
(8) Drag to place all labels.
  The labels are placed.
(9) Click [Create Schematic]
-> [Port].
(10) Select a port shape, specify the port name, and then click "OK".
(11) Place the port.

Bus Rule settings are configured after bus placement.
It is necessary to place a label to a wire connected to a bus in order to specify the Net Name.


Ripper Settings

Ripper (angled portion of the wire connected to the bus) Settings
When creating wires, it is possible to confirm and change settings from Property.
The following explains the ripper confirmation location.
 

This also applies to the Bus corner.

Also, rippers are automatically created when buses are connected to each other.

Connect buses to each other After connection


Bus Rule Settings

Bus Rule Settings
Configure the Bus Rules for the placed buses.
By configuring Bus Rules, it is possible to check whether there are insufficient labels for wires connected to a bus when running ERC.
It is possible to prevent mistakes such as forgetting to connect or forgetting to place a label.
To configure the Bus Rules, connect the port that imports the Bus Rules to the bus.

For more details about placing ports, refer to Placing Ports.
For more details about the Bus Rule format, refer to Bus Rule Format.


Bus Rule Format

The following explains the Bus Rule Format. The bus format consists of three parts: a label identifier, the range of label number and an operator.
 

Bus Rule Terms

Term Definition

Label Identifier

A character(s) which appears before a label number. Labels with the same name as the identifier can be connected to the bus wire.

Label Number

A number which comes after a label identifier.

Range of Label Number

The range of label number which allows connection. This is specified in the following format and labels within the range can be connected to the bus wire.
Format: [Label Number(From):Label Number(To)]

Operator

An OR operator used to specify multiple rules. It is expressed by a "/".

 

Bus Rule Example

Bus Rule Definition

DA[00:20]/D/A

Allows connection of wires with labels from DA00 to DA20, D and A.


Each Operation for Drawing Buses

The following explains each operation for drawing a bus.

Selecting Bus Menu
Changing Bus Corner Angle
Switching Angle
Pushback Bus
Canceling Bus
Exiting Bus Mode

 

Selecting Bus Menu

Select [Create Schematic] -> [Bus]

There are several other ways to perform this. Refer to About Executing Menus.

Changing Bus Corner Angle

The bus corner angle can be changed freely.

Bus Corner Bending Angle

45 degrees 90 degrees Free

The following is the operation for changing the bus corner bending angle.

Method 1: Right click and select [Change Bending Angle].
Method 2: Press "S" on the keyboard.
* It can also be confirmed and changed from the Property Window.

 


Switching Bus Angle
Before Switching After Switching

The following is the operation for switching the angle.

Method 1: Right click and select [Switch Angle].
Method 2: Press "X" on the keyboard.
* It can also be confirmed and changed from the Property Window.

 

It is also possible to determine the pulling direction by tracking using the mouse pulling direction.

When pulling to the right side first When pulling to the bottom first

 


Pushback Bus

When creating a bus, you can pushback the corner to the previous status.

Before Pushback After Pushback

The following is the operation for executing pushback.

Method 1: Right click and select [Pushback].
Method 2: Press "BackSpace" on the keyboard

 

Canceling Bus

When creating a bus, it is possible to return to the status before drawing by canceling the bus being created.

Before Canceling After Canceling

The following is the operation for executing pushback.

Method 1: Right click and select [Cancel].
Method 2: Press "Escape" on the keyboard.

 


Exiting Bus Mode

The following is the operation for exiting Bus mode.

When not creating a bus,

Method 1: Right click and select [Cancel].
Method 2: Press "Escape" on the keyboard.